Investigating the Interplay between Executive Function, Apolipoprotein E4, and Falls in Older Adults with Normal Cognition, Mild Cognitive Impairment, and Alzheimer's Dementia

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Description
Falls are a public health concern for older adults with or without cognitive impairment, including clinical Mild Cognitive Impairment (MCI) and Alzheimer’s Disease (AD) dementia. Executive function (EF) is linked to falls and is notably impaired in individuals with MCI…

Falls are a public health concern for older adults with or without cognitive impairment, including clinical Mild Cognitive Impairment (MCI) and Alzheimer’s Disease (AD) dementia. Executive function (EF) is linked to falls and is notably impaired in individuals with MCI and AD dementia. However, it is unclear which EF assessments are associated with falls in older adults with intact cognition, MCI, and AD dementia. Apolipoprotein E4 (ApoE4) increases the risk of MCI and AD dementia, with limited information suggesting decreased EF and gait impairment in ApoE4 carriers. The purpose of this study was to 1) investigate the relationships between EF assessments and falls (fall history and future fall) by cognitive status (intact cognition, MCI, AD dementia) and 2) determine if ApoE4 moderates the relationship between EF and falls across cognitive status. EF assessments included Digit Span (DS), Trail Making Test (ΔTMT), Stroop Interference Test, Controlled Oral Word Association assessments of phonemic and semantic fluency (COWAC), and Clock Drawing Test. Binary logistic regression was used with secondary data to analyze the EF and falls relationship. Results showed a significant association of the ΔTMT with fall history but may not be appropriate for use with people with AD dementia due to a floor effect. Significant interaction effects were shown between AD dementia and DS, ΔTMT, and EF as a latent variable, where individuals with a fall history had better EF performance. The interaction effects are influenced by the lower percentage of reported falls in people with severe AD dementia. In the second aim, a confounding effect exposed a potential four-way interaction where higher EF in ApoE4 non-carriers with AD dementia experienced a future fall without a fall history. Overall, more research is needed to determine which EF assessments are best suited for fall risk assessment and whether ApoE4 plays a role in the relationship between EF and falls. Since the low percentage of reported falls in people with severe AD dementia exposed a differing trend between EF and falls, more research is needed to develop valid and reliable tools for collecting fall data in individuals with severe AD dementia.
Date Created
2023
Agent

The Neural Control and Adaptability of Reactive Balance Responses in Parkinson’s Disease

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Description
Parkinson's Disease (PD) is a progressive neurodegenerative disorder that affects movement and balance control. Falls are a common and often debilitating consequence of PD, and reactive balance control is critical in preventing falls. This dissertation aimed to determine the adaptability…

Parkinson's Disease (PD) is a progressive neurodegenerative disorder that affects movement and balance control. Falls are a common and often debilitating consequence of PD, and reactive balance control is critical in preventing falls. This dissertation aimed to determine the adaptability and neural control of reactive balance responses in people with PD. Aim 1 investigated whether people with PD at risk for falls can improve their reactive balance responses through a 2-week, 6-session training protocol. The study found that reactive step training resulted in immediate and retained improvements in stepping, as measured by the anterior-posterior margin of stability (MOS), step length, and step latency during backward stepping. The second aim explored the neural mechanisms behind eliciting and learning reactive balance responses in PD. The study investigated the white matter (WM) correlates of reactive stepping and responsiveness to step training in PD. White matter was not significantly correlated with any baseline stepping outcomes. However, greater retention of step length was associated with increased fractional anisotropy (FA) within the left anterior corona radiata, left posterior thalamic radiation, and right and left superior longitudinal fasciculi. Lower radial diffusivity (RD) within the left posterior and anterior corona radiata were associated with retention of step latency improvements. These findings highlight the importance of WM microstructural integrity in motor learning and retention processes in PD. The third aim examined the role of the somatosensory system in reactive balance control in people with PD. The tactile and proprioceptive systems were perturbed using vibrotactile stimulation during backward feet-in-place balance responses. The results showed that tactile and proprioceptive stimulation had minimal impact on reactive balance responses. Small effects were observed for delayed tibialis anterior (TA) onsets with proprioceptive stimulation at a medium intensity. Overall, this dissertation provides insights into improving reactive balance responses and the underlying neural mechanisms in PD, which can potentially inform the development of targeted interventions to reduce falls in people with PD.
Date Created
2023
Agent

MRtrix3 Pipeline Development for Processing Diffusion Weighted Images in Aging in Autism Study

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Description
Diffusion weighted imaging utilizes magnetic resonance imaging to capture white matter tracts in the brain. Many studies have utilized this technique to measure white matter structures looking for evidence of anatomical and physiological differences in Autism Spectrum Disorder (ASD). Parkinsonian-like…

Diffusion weighted imaging utilizes magnetic resonance imaging to capture white matter tracts in the brain. Many studies have utilized this technique to measure white matter structures looking for evidence of anatomical and physiological differences in Autism Spectrum Disorder (ASD). Parkinsonian-like symptoms have been documented and self-reported in aging autistic individuals, opening up questions about a possible link between ASD and an increased risk of Parkinson’s Disease. Utilizing MRtrix3, an image processing proof-of-concept pipeline was developed for the Autism and Brain Aging (ABA) lab to generate and visualize the brain’s structural connectivity network in these populations of interest. The pipeline provides the opportunity for white matter tractography analysis in the lab’s Aging in Autism study.
Date Created
2023
Agent

The Effects of Pediatric Assisted Cycle Therapy (PACT) on Leisure Time Physical Activity in Children with Down Syndrome (DS)

Description

Research has shown the benefits of exercise on people with (DS), and how it affects their quality of life (Maïano et al. 2019). However, many studies have also shown that the majority of people with DS do not meet the…

Research has shown the benefits of exercise on people with (DS), and how it affects their quality of life (Maïano et al. 2019). However, many studies have also shown that the majority of people with DS do not meet the national minimum requirements for physical activity per day (Phillips et al. 2011). The current study will focus on Pediatric Assisted Cycle Therapy (PACT) as exercise and specifically its effects on children with DS. The goal is to improve the general behavioral skills of children with DS, which in turn can improve their quality of life. We predict that, based on pilot data (Gomez, 2015; Parker, 2016), GLTEQ will increase their total activity score following 8 weeks of PACT in young children with DS. The Godin Leisure Time Exercise Questionnaire was used to measure the participants’ participation levels in leisure time activity. Participants were involved in an 8-week intervention, in which they biked (PACT) for 30 minutes, twice a week. GLETQ was measured pre and post intervention and assessed using the scale provided by the GLETQ. The data from this study has shown a positive correlation between Leisure Time Activity and PACT. Overall, a mean increase in raw activity score in the GLETQ was shown.

Date Created
2023-05
Agent

Ethnic Differences in Dementia Revealed by Multimodal Imaging.pdf

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Description
Inflammatory genes are known to only show in African Americans and non-Hispanic Whites. The objective of this study was to observe the correlation from the obtained data of the prevalence of the APOE ε4 genotype. We examined cerebral free-water, a…

Inflammatory genes are known to only show in African Americans and non-Hispanic Whites. The objective of this study was to observe the correlation from the obtained data of the prevalence of the APOE ε4 genotype. We examined cerebral free-water, a marker of neuroinflammation, hippocampal volume, and volume of white-matter hyperintensities in African Americans (AA) and non-Hispanic Whites who were categorized in groups based on whether they had APOE ε4 allele or not. AA had lower prevalence of APOE e4 genotype than non-Hispanic Whites. AA groups have a slightly higher hippocampal volume compared to the Non-Hispanic White (NHW) groups. African Americans also reported increased white-matter hyperintensities and cerebral free-water. Hippocampal atrophy is associated with Alzheimer's disease, this might suggest that the AA groups have a lower risk of Alzheimer's, although further research is needed to confirm this relationship. Lastly, our findings also suggest other potential socioeconomic factors that could contribute to increased incidence of dementia among AA and potential resilience factors early in the course of Alzheimer’s disease process.
Date Created
2023-05
Agent

Stephens_Spring_2023.pdf

Description
Inflammatory genes are known to only show in African Americans and non-Hispanic Whites. The objective of this study was to observe the correlation from the obtained data of the prevalence of the APOE ε4 genotype. We examined cerebral free-water, a…

Inflammatory genes are known to only show in African Americans and non-Hispanic Whites. The objective of this study was to observe the correlation from the obtained data of the prevalence of the APOE ε4 genotype. We examined cerebral free-water, a marker of neuroinflammation, hippocampal volume, and volume of white-matter hyperintensities in African Americans (AA) and non-Hispanic Whites who were categorized in groups based on whether they had APOE ε4 allele or not. AA had lower prevalence of APOE e4 genotype than non-Hispanic Whites. AA groups have a slightly higher hippocampal volume compared to the Non-Hispanic White (NHW) groups. African Americans also reported increased white-matter hyperintensities and cerebral free-water. Hippocampal atrophy is associated with Alzheimer's disease, this might suggest that the AA groups have a lower risk of Alzheimer's, although further research is needed to confirm this relationship. Lastly, our findings also suggest other potential socioeconomic factors that could contribute to increased incidence of dementia among AA and potential resilience factors early in the course of Alzheimer’s disease process.
Date Created
2023-05
Agent

Ethnic Differences in Dementia Revealed by Multimodal Imaging

Description

Inflammatory genes are known to only show in African Americans and non-Hispanic Whites. The objective of this study was to observe the correlation from the obtained data of the prevalence of the APOE ε4 genotype. We examined cerebral free-water, a…

Inflammatory genes are known to only show in African Americans and non-Hispanic Whites. The objective of this study was to observe the correlation from the obtained data of the prevalence of the APOE ε4 genotype. We examined cerebral free-water, a marker of neuroinflammation, hippocampal volume, and volume of white-matter hyperintensities in African Americans (AA) and non-Hispanic Whites who were categorized in groups based on whether they had APOE ε4 allele or not. AA had lower prevalence of APOE e4 genotype than non-Hispanic Whites. AA groups have a slightly higher hippocampal volume compared to the Non-Hispanic White (NHW) groups. African Americans also reported increased white-matter hyperintensities and cerebral free-water. Hippocampal atrophy is associated with Alzheimer's disease, this might suggest that the AA groups have a lower risk of Alzheimer's, although further research is needed to confirm this relationship. Lastly, our findings also suggest other potential socioeconomic factors that could contribute to increased incidence of dementia among AA and potential resilience factors early in the course of Alzheimer’s disease process.

Date Created
2023-05
Agent

Optimization of the Identification Process of Imaging Markers of Health in Middle-Aged & Older Adults Susceptible to Cognitive Decline using Python Programming Analysis

Description

This paper describes a project involving the optimization of the analysis process of FreeSurfer and ANTS Registration for neuroscience analytics of patients at risk of cognitive decline using Nipype. The paper details the process of discovering more about Nipype, learning…

This paper describes a project involving the optimization of the analysis process of FreeSurfer and ANTS Registration for neuroscience analytics of patients at risk of cognitive decline using Nipype. The paper details the process of discovering more about Nipype, learning to use a supercomputer, and implementing the open-source python code to fit the needs of the research lab. Nipype is a python-based initiative to unify the various software packages used within the neuroscience community for data analysis. This paper also serves as documentation of the steps taken to complete the project so that future students are able to continue the optimization process to result in one cohesive workflow in which data is able to flow through a unified pipeline of analysis in the future.

Date Created
2023-05
Agent
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